Reclining mechanism for wheelchairs and the like



June 29, 1965 D. E. RUGG ETAL 3,191,990

RECLINING MECHANISM FOR WHEELCHAIRS AND THE LIKE 3 Sheets-Sheet 1 Filed May 31, 1962 INVENTORS RUGG ORR A TTORNE Y DONALD E. WILLIAM R. %%i

June 29, 1965 D. E. RUGG ET AL 3,191,990

RECLINING MECHANISM FOR WHEELCHAIRS AND THE LIKE Filed May 31, 1962 5 Sheets-Sheet 2 iOO r 4e I 95 46 46' 1 5 44 m2 PI lol H- 4 INVENTOR.

DONALD E. RUGG WILLIAM R. ORR

A TTORNE Y June 29, 1965 D. E. RUGG ET AL 3,191,990

RECLINING MECHANISM FOR WHEELCHAIRS AND THE LIKE Filed May 31, 1962 3 Sheets-Sheet I5 lNVENlOR; DONALD E. RUGG WILLIAM R. ORR

ATTORNEY United States, Patent O 3,191,990 RECLINING MECHANISM FOR WHEELCHAIRS AND THE LIKE Donald Edwin Rugg, 1452 S. Birch, and William R. Orr, 1245 S. Fairfax, both of Denver, Colo. Filed May 31, 1962, Ser. No. 199,089 12 Claims. (Cl. 297-83) without assistance and in such a way that the handicapped person can vary or change his disposition in the chair between an'upright and a full reclining position in an effective and improved manner. It is another object of the present invention to make provision for areclining mechanism for use in wheelchairs and the like for invalids and handicapped persons which can be controlled for adjustment to any desired position between a substantially upright and a full reclining position without effort or physical shifting of the occupant in any way, and which is so constructed and arranged as to closely conform to natural body movement when being raised or lowered to the desired disposition and relation.

It is a further object :of the present invention to provide a chair structure and the like having a back and headrest moveable between an upright position wherein the headrest isin normally retracted relation and a reclined position wherein the headrest is in head-supporting relation, the headrest remaining in stationary head-supporting relation throughout the major degree of movement of the back into the full reclining position; also, having a back and seat being moveable between an upright and reclined position with the seat undergoing limited independent movement to better conform to changes in body attitude an upright and fully reclined relation, as Well as to provide for novel and improved linkage to carry out the above and with improved, accurate means of control of the linkage so that the position may be changed by the individual in an easy dependable manner without outside assistance.

The above and other objects, advantages and features of the present invention will become more readily appreciated and understood from a consideration of the following detailed description taken together with the accompanied drawings, in which:

FIGURE 1 is a rear view of a preferred form of wheelchair in accordance with the present invention.

FIGURE 2 is a side elevational view of the wheelchair shown in FIGURE 1. I

FIGURE 3 is a detailed plan view showing the main frame and actuator assembly for the wheelchair.

FIGURE 4 is a detailed sectional view showing a preferred form of balance rod assembly used in supporting and controlling the movement of the headrest for the wheelchair; and

FIGURES 5 to 8 are kinematic diagrams illustrating the interrelationship between the linkage incorporated in the wheelchair of the present invention and illustrative.

of intermediate positions between a substantially upright and fully reclined position.

3,1913% Patented June 29, 1965 ice Referring in more detail to the drawings, the present invention is best exemplified by reference to an electric wheelchair 11) for handicapped persons. Broadly, the wheelchair is illustrated as being comprised of a back 12, seat 13, headrest 14 at the upper end of the back member and a footrest 15 at the forward end of the seat 13. The back 12 and seat 13 are carried on a common frame 16, which in turn rests on a pair of front wheels 18 and swivelled back wheels 19. The front wheels are carried for rotation at the lower end of the frame 16 and the back wheels are individually connected to the frame through heavy 'duty casters 22. I

The speed and directional control system for the wheelchair forms no part of the present invention, and merely for the purpose of illustration, the frame 16 serves as a support for motors 23 to individually drive each front wheel through a belt drive system 24. A common battery source 25 and relay control box 26 for the motors23 are controlled through an operator control box 28 mounted on the seat assembly in a location'easily accessible to the operator. This control system is essentially designed to provide the necessary power for directional and speed control of the wheelchair and, in a manner to be described, to supply the necessary power, through a third motor 30, for control and actuation of the reclining mechanism for the wheelchair. In this relation, the frame also supports the main drive or actuator assembly 32 for the reclining mechanism in order to initiate movement of the back and seat members from a substantially upright posi tion through intermediate degrees of inclination to a fully reclined position.

The frame 16 preferably consists'of an outer, generally U-shaped, support member 34 having a rear crossbar 35 welded thereto. A series of spaced, parallel guide tracks 36 are mounted to extend horizontally between the rear crossbar 35 and forward extremity 34 of the supporting member. The outermost spaced tracks 36 have forward continuations 37 curving downwardly from the support member 34, along with vertical posts 38 extending downwardly from the rear crossbar 35. A lower, spaced member 39 interconnects each post 38 and downward continuation 37, and driveshaft 20 for each front wheel is mounted in bearings, not shown, attached to the lower frame members 39. Located just abovethe back wheels 19, a crossbar 40 extends between vertical supporting posts 41 and acts as the main support for a mounting bracket 42 for balance rod assembly 17. Here, the mounting bracket 42 consists of spaced welded tubular members connected between the main crossbar 40 and a lower crossbar 43 extending between the lower end of vertical posts 38, and spaced pivot pins 44 are positioned and supporting elements, and preferably all supporting members for the frame consist of welded, thin-walled, steel tubing so that the frame is light weight but sturdy.

. The back 12 is preferably in the form of an open frame supporting a back cushion, represented at 51. The frame 50 is defined by a pair of spaced, vertically extending'tubular members 52 interconnected at spaced intervals by horizontal cross members 53'. At the lower end, each member 52 has a downward extension 54 and supporting brace 54' with a bushing 56 carried for rotation on a guide shaft 55. In addition, a series of spaced rollers 58 are journaled on the guide shaft in alignment with guide, rails 36' welded to the tracks 36. In a'manner to be described, the actuator assembly 32 will cause forward and rearward horizontal movement of the guide shaft to initiate lowering and raising of the wheelchair between the upright and reclined positions.

The seat 13 is mounted in spaced relation above the frame 16 and guide tracks 36, and is comprised broadly of a lower supporting frame 6%), upper seat frame 62 and seat cushion 63 positioned on the frame 62. The lower supporting frame 60 is comprised of longitudinally extending tubular members 64 with cross members, not shown, interconnecting the members 64 at spaced intervals therealong. Rollers 66 are journaled on pins projecting inwardly from each member 64 in order to support the seat frame 62 for slidable movement thereon. The members 64 for lower frame 60 are mounted in spaced relation above the main supporting frame 34 by means of forward, fixed pivotal connections through a pair of spaced pivot links 70 to vertical support rods 67 the latter forming vertical continuations of horizontal supporting rods 67' secured to each armrest 68. The pivot link 70 also pivotally interconnects the lower supporting frame 60 and the footrest 15, the rearward extremity of the frame 60 is secured in pivotal relation to the back frame 59 by means of a movable pivot link 71 connected to the back in spaced relation above the guide shaft 55. In this way, the lower supporting frame 60 will be free to undergo limited tilting movement about the fixed pivot point, defined at the point of interconnection between the frame and support rods 67, as the back is raised and lowered.

In a unique manner, the seat 13 undergoes limited horizontal sliding movement as the back is tilted between the upright and fully reclined position, in order to conform to changes in the attitude and disposition of the handicapped person. Accordingly, the frame consists of a pair of spaced rails 72 braced with cross members 73 at the front and back and cove-red with a thin, cushioned supporting plate 74. The rails 72 are aligned with rollers 66 so as to be free to slide therealong and the extent of sliding movement is governed by connecting straps 75 fastened on either side of the supporting frame between the seat and the back supporting members 52. Thus, when the back is in nearly vertical relation the seat is in a forward position, as illustrated in FIGURE 2; as the back tilts downwardly, however, the seat is pulled back along the rollers for a limited distance which motion prevents the individual from sliding or shifting relative to the seat during the sitting up or reclining process. The arm support member 68 which is connected into the lower supporting frame 60 prevents side motion of the seat as it is caused to undergo limited sliding movement. The seat cushion 63 can be composed of any suitable padding material and is fastened directly to the supporting plat 74 so as to directly follow the movement of the seat supporting frame 62.

The armrests 68 are defined by generally U-shaped members fitted with fiat padded members 68' along the upper horizontal portions thereof, and the control switch box 28 is shown as being attached to the outside of one armrest. Additionally, the footrest 15 is of conventional construction having for example a leg plate 76 and foot plate 77. The footrest is pivoted to "swing about the pivot link 70 in response to movement of a follower link including a bearing 78 secured to the front end of an A frame 80, and the frame is connected to opposite ends of the shaft 55 to follow the movement thereof as best seen from FIGURE 3. In the lowered position as shown in FIGURE 2, the footrest can be adjusted by means of an elongated slot 81 to rest at any position from vertical to about 20 degree-s from vertical without affecting its movement between the raised and lowered positions in a manner to be described in relation to FIGURES and 8.

Another important feature of the present invention resides in the disposition and arrangement of the headrest 14 in relation to the back and seat members. The headrest includes a frame 84 having cross members 85 and a padding 86 secured to the frame. The frame is pivotally connected as at 87 to the top extremity of the back supporting frame 50, and the balance rod assembly 17 is in turn pivotally connected to the headrest frame at 88. Broadly, the balance rod assembly is arranged in such relation to the headrest that when the back is in the substantially upright position the headrest is folded or collapsed behind the back as illustrated in FIGURE 2. As the .back is caused to recline, however, the balance rod will force the headrest to move gradually into head-supporting relation so that after the back has undergone a limited degree of angular movement the headrest will be in head-supporting relation to form a direct upward extension of the back. Releasable locking means associated with the balance rod serve to support the headrest in this relation, and thereafter the balance rod will yield or stretch under continued angular reclining movement of the back until the chair is in the fully reclined position. In this connection, the balance rod in association with the releasable locking means operates first to provide sufficient support to move the headrest into desired relation and to lock it in place, as Well as to provide a force behind the back tending to balance the weight of the individual in approaching the reclining position. This reaction force will accordingly remove most of the load from the actuator assembly both when raising and lowering the back, and again the entire operation is best understood from a consideration of FIGURES 5 to 8.

In the preferred form, the balance rod assembly 17 is comprised of a lower cylinder 90 pivotally connected at its lower end to the mounting bracket 42, hereinbefore described, and as best seen from FIGURE 4. In more detail, the cylinder is made up of an outer sleeve 91 p sitioned between the bearing 46 and an upper bearing 92. Positioned for movement through the cylinder is a hollow balance shaft 94 having an upper bifurcated end and a lower enlarged end 95 providing a shoulder 96 to abut against a reduced shoulder 46 on the bearing 46. The balance shaft is normally biased into abutting relation against the bearing by means of a tension spring 98 c iled in outer concentric relation about the lower end of the piston rod and secured in place within the cylinder between the enlarged end 96 and upper 92. A release rod 100 extends through the shaft 94 having a lower threaded end with a nut 101 positioned thereon to abut end plate 192. The rod 106 extends through the greater length of the piston rod then outwardly through the open bifurcated end of the shaft 94 into connection with a pawl or hook 104. A catch is mounted on the back-support member 50 to accommodate the hook, in which relation the headrest will be locked in fixed, extended relation to the back.

As the back 13 is tilted downwardly the force of the spring 98 initially will hold the piston rod 94 in stationary relation against the Weight of the headrest so as to cause the headrest to pivot upwardly into head-supporting relation with the back. Here, the pawl 104 will have moved into engagement with the catch so as to lock the headrest in place and to support the head as the back continues to recline; otherwise, the headrest would tend to collapse under the weight. As the back continues to recline with the headrest in locked relation it will overcome the resistance of the spring 98 causing it to stretch and causing the piston rod to move downwardly through the cylinder and through the lower end of the bearing 46 until the fully reclined or horizontal position is reached. In raising the back, the piston rod will of course return through the cylinder and when the end plate 102 moves into abutment with the lower end of the bearing, the rod 100 will tighten sufficiently to pull and to release the pawl so that the headrest will be free to collapse as the back returns to the substantially upright position.

Various drive means may be employed to drive the reclining mechanism between the upright and horizontal position and, for the purpose of illustration, the actuator assembly 32 is'prefer-ably positioned to initiate movement of the lower guide shaft 55 alon-g the rails 36 to cause simultaneous movement of the back and headrest, seat and footrest sections. In this form, the actuator assembly is defined by a drive screw 110 positioned to extend horizontally in spaced parallel relation between the inner pair of tracks 36 and being mounted between front and back bearing blocks 111 and 112, respectively. One end of the drive screw is connected for rotation into the outputside of the reversible electric motor 30; in turn, the guide shaft 55 is preferably formed in two sections having near ends journaled in a drive nut 114 which is threaded for horizontal advancement in'response to rotation of the drive screw 110. To control the dire-ction of advancement, a control lever 28 on the control box 28 is connected through a toggle switch and control relay, not shown, into the reversible motor 30. When moved to the down position the motor will be energized through the battery souice to drive the screw in a left-hand direction thereby causing forward advancement of the drive nut 114 and lowering of the back 12. When the drive nut reaches its forward limit of travel it will engage a limit stop in the form of micro switch 115 thereby interrupting the current of the relay coil and stopping the motor. When the control lever 28 is moved to an up position a separate relay is closed energizing the motor to rotate the drive screw in the opposite, right-hand direction so as to cause retraction of the drive nut and raising of the back, again until the drive nut contacts a limit stop defined by microswitch 116; the control lever 29 controls the speed and directional control of the wheelchair in a conventional manner. 7

A better understanding of the operation of the reclining mechanism can be obtained from a consideration of FIGURES 5 to 8 illustrating somewhat diagrammatically the inter-relationship between parts in moving from the substantially upright position, as shown in FIGURE 5, to the reclined position, shown in FIGURE 8. As noted, there is a single fixed point of support for the reclining mechanism, that being at the-point of interconnection between the lower supporting frame 64 and support rod 67 adjacent to the pivot point 70, so that the back, seat and footrest portions will be restricted in movement about that'point. Considering first the movement of the back and'headrest, as the back begins to recline in response to forward horizontal advancement of the drive shaft 5 5 the spring 98 willinitially prevent the shaft 94 from sliding in its lower bearing, thus forcing the headrest to pivot back and upas indicated in FIGURE 6. When the 'headrest has pivoted to a position such that it forms an extension of the back, the pawlwill move into engagement with thecatch to prevent any further pivoting, as seen from -FIGURE 7. In this relation, with the back atabout'30 degrees from the vertical the spring 98 will begin to stretch thereby allowing the rod 94 to slide through its lower bearing, and the balance rodand spring will continue to yield until the back and headrest are at an angle of about 10 degrees from horizontal, as represented in FIGURE 8. In this position the chair is fully reclined. As pointed out before, the spring constraining the balance shaft performs two functions: First, to provide suflicient support to keep the headrest against the mechanical "stop or latch thus forming an extension of the back; and secondly, to counterbalance the weight of the individual as the reclining position is approached.

Now considering the relative movement of the seat and footrest members, when the back is in the upright position, the seat is in the forward position in relation to the lower supporting frame 64. However, as the back is lowered, the seat is pulled back under the force of the connecting straps 75 thereby to follow the natural .body movement or rearward displacement or the indi vidual as the back is reclined. Otherwise, were the seat 6 left stationary or caused to move forwardly as the back reclines this would cause a gradual shifting of the individual forwardly in relation to the seat under repeated movement and would be of particular disadvantage for seriously disabled persons.

Preferably, with the actuator nut 1:14 at the back position of travel the seat will slope down from front to back at an angle of about 5 degrees, the back sloping at an angle of about 10 degrees from the vertical, this i being illustrated in FIGURE SQ As the actuator nut advances forwardly the back will swing down to an angle of about 10 degrees from the horizontal and the seat inclination'will increase to about 12 degrees from horizontal. Simultaneously, the footrest is gradually raised under the urging of the A frame to a substantially horizontal position, as illustrated in FIGURE 8. From the foregoing description of a preferred form of wheelchair and reclining mechanism, in accordance with the present invention, it will be readily appreciated that a number of features and advantages would be applicable to other reclining articles of furniture, such as hospital beds, beds for handicapped persons, as well-as various types of stationary or moveable chairs. Of course the principal, broad advantage of the present invention resides in the ability of the operator to be completely mobile and capable of reclining and raising himself repeatedly without the aid -or assistance of another person. In addition, the manner in which the seat is caused to move in relation to the back in order to prevent'sliding or shifting of the body during the reclining or sitting up process as Well as the construction and arrangement of the balance rod assembly to remove the load from the actuator assembly are believed of importance. Furthermore, angular adjustment of the footrest in the sitting position Will not affect the reclined positionor relationship between the back and seat and the entire assembly is very maneuverable, comparatively simple and economical to manufacture in that it can function using asingle drive or actuator assembly alone.

A number of variations and changes can be made entirely within the present invention such as in the particular dimensional and angular relationship between parts, as well as the particular means of control employed to carry out the reclining operation. Thus, the drive system and the reclining mechanism could very easily be bydraulically controlled; for example the 'headrest may be raised into desired position before any motion has taken place in the back and footrest. It is to be understood that various other modifications and changes may be resorted to without departing from the spirit and scope of the present invention, as defined by the appended claims and equivalent, thereof.

What is claimed is: l

1. In a reclining chair having a back member and a seat member, means supporting said back member for angular movement between a forward substantially upright position and a rearward substantially reclined position, means supporting said seat member for horizontal sliding movement thereon, and pivotal connecting means between said back and seat members being defined by at least one connecting strap inclining rearwardly from said seat member to said back member and having opposite ends pivotally connected to said seat member and back member, respectively, to provide for independent horizontal sliding movement of said seat in following the angular movement of said back member between the upright and reclined positions.

2. In a reclining chair, a main supporting frame, a back member including guide means supporting said back for controlled directional movement between a substantially upright position and a reclined position relative to said frame, a seat member including a lower support being pivotally connected at its rearward end to said back member above said guide means and being connected at its opposite forward end in fixed pivotal rela- 4 tion to said frame, and drive means associated with said guide means being operative to provide for vertical tilting of said seat member about its point of fixed pivotal connection to said frame in response to controlled directional movement of said back member.

3. In a reclining chair according to claim 2, a footrest pivotally connected to said lower supporting means for said seat member, said footrest being adapted for movement between a downwardly extending, substantially vertical position, actuating means drivingly connected to said guide means to initiate angular movement of said back member between the upright and reclined positions, and said actuating means including means being drivingly connected to said footrest to correlate angular movement of said footrest with the angular movement of said back member.

4. In a reclining chair, a main supporting frame, a back member including guide means at the lower end of said back member being slidable relative to said frame to provide for angular movement of said back member between a substantially upright position and a reclined position, a seat member having lower support means pivotally connected to said back member above said guide means and slide means above said lower support means supporting said seat for independent horizontal sliding movement in relation to said lower support means, and connecting means between said seat and back members to provide for horizontal sliding movement of said seat independently of said lower support means in response to angular movement of said back member.

5. In a reclining chair according to claim 4, said connecting means being defined by at least one connecting strap inclining rearwardly and upwardly from said seat member to said back member and having opposite ends pivotally connected to said seat member and back member, respectively.

6. In a reclining chair according to claim 4, said guide means being defined by a horizontally extending guide track mounted in fixed relation on said frame and roller means at the lower end of said back member being supported on said track for slidable movement therealong, and drive means drivingly connected to said roller means to control sliding movement of said roller means along said track.

7. In a reclining chair according to claim 2, said seat member additionally including an upper seat support slidably disposed on said lower support and being pivotally connected to said back independently of said lower support for limited horizontal movement in response to controlled directional movement of said back member.

8. In a reclining chair according to claim 2, said guide means being carried on said frame and including at least one horizontally extending guide track and roller means at the lower end of said back member being supported on said track for slidable movement therealong.

9. In a reclining chair according to claim 8, said drive means being interposed between said roller means and 8. said frame to control the sliding movement of said roller means along said track.

10. A reclining chair comprising a main supporting frame, a back member including a lower end portion disposed for sliding movement relative to said main-supporting frame thereby to provide for angular movement of said back member above said lower end portion between a forward substantially upright position and a rearward reclined position, a seat including a lower support member on said frame and pivotally connected to said back member above the lower end thereof, said seat having seat-supporting means slidable on said lower support with means pivotally interconnecting said seat-supporting means and back member to provide for limited sliding movement of said seat-supporting means in a direction following the forward and rearward direction of movement of said back member, a headrest pivotally secured above said back member in normally collapsed relation thereto and yieldable support means for said headrest to urge said headrest into head-supporting relation in response to limited angular reclining movement of said back member, releasable locking means to hold said headrest in fixed, head-supporting relation with said back, said yieldable support means being movable with said headrest upon continued reclining movement of said back supporting member, and actuating means drivingly connected to the lower end of said back member to initiate sliding movement of said lower end and simultaneous movement of said seat end headrest therewith.

11. A reclining wheelchair according to claim 10 wherein a footrest is pivotally connected to said seat, and a follower link interconnecting said footrest and said actuating means to initiate angular movement of said footrest in correlation with the angular movement of said back.

12. A reclining wheelchair according to claim 11, said follower link being adjustable in length thereby to regulate the angular disposition of said footrest in relation to said wheelchair.

References Cited by the Examiner UNITED STATES PATENTS 465,275 12/91 Kennedy et al. 29783 2,676,643 4/54 Miller et a1. 29783 2,694,437 11/54 Glaser 29783 2,714,922 8/55 McKibban et a1. 29783 2,753,920 7/56 Ranger 29783 2,850,073 9/58 Smith 248430 2,850,078 9/58 Lorenz 29790 X 2,859,797 11/58 Mitchelson 29761 2,895,539 7/59 Ragsdale et a1. 29783 2,927,630 3/60 Sichelschmidt 29783 2,929,439 3/60 Tanaka et al 297330 2,944,595 7/ Barabas et a1. 29785 2,952,303 9/ 60 Spound et al 29761 FRANK B. SHERRY, Primary Examiner. 

1. IN A RECLINING CHAIR HAVING A BACK MEMBER AND A SEAT MEMBER, MEANS SUPPORTING SAID BACK MEMBER FOR ANGULAR MOVEMENT BETWEEN A FORWARD SUBSTANTIALLY UPRIGHT POSITION AND A REARWARD SUBSTANTIALLY RECLINED POSITION, MEANS SUPPORTING SAID SEAT MEMBER FOR HORIZONTAL SLIDING MOVEMENT THEREON, AND PIVOTAL CONNECTING MEANS BETWEEN SAID BACK AND SEAT MEMBERS BEING DEFINED BY AT LEAST ONE CONNECTING STRAP INCLINING REARWARDLY FROM SAID SEAT MEMBER TO SAID BACK MEMBER AND HAVING OPPOSITE ENDS PIVOTALLY CONNECTED TO SAID SEAT MEMBER AND BACK MEMBER, RESPECTIVELY, TO PROVIDE FOR INDEPENDENT HORIZONTAL SLIDING MOVEMENT OF SAID SEAT IN FOLLOWING THE ANGULAR MOVEMENT OF SAID BACK MEMBER BETWEEN THE UPRIGHT AND RECLINED POSITIONS. 